Method and system for an asymmetric PHY operation for ethernet A/V bridging and ethernet A/V bridging extensions

ABSTRACT

Signals may be communicated with A/V Bridging services between an upstream link partner and a down stream link partner, each comprising an asymmetric multi-rate Ethernet physical layer (PHY). High bandwidth A/V signals may be transmitted from the upstream link partner and low bandwidth signals may be transmitted from the downstream link partner. One or more of a time stamp, a traffic class and/or a destination address may be utilized in generating PDUs as well as data rate request and a resource reservation messages via the asymmetric Ethernet PHY. The receiving link partner may register for deliver of the PDUs. An aggregate communication rate may be distributed evenly or unevenly among one or more links for transmission and aggregated upon reception via asymmetric multi-rate Ethernet PHY operations. Compressed, uncompressed, encrypted and/or unencrypted signals may be handled. Signal processing may comprise echo cancellation, cross talk cancellation, forward error checking and equalization.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This application is a continuation of U.S. application Ser. No.12/942,188, filed Nov. 9, 2010, now U.S. Pat. No. 8,179,910, which is acontinuation of U.S. application Ser. No. 11/861,037, filed Sep. 25,2007, now U.S. Pat. No. 7,835,374, which in turn makes reference to andclaims priority to U.S. Provisional Application Ser. No. 60/917,870,filed on May 14, 2007, entitled “Method and System for EthernetAudio/Video Bridging,” which is hereby incorporated herein by referencein its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to high-speed wiredcommunication. More specifically, certain embodiments of the inventionrelate to a method and system for an asymmetric PHY operation forEthernet A/V Bridging and Ethernet A/V Bridging extensions.

BACKGROUND OF THE INVENTION

The multimedia consumer electronics market is rapidly evolving withincreasingly sophisticated audio/video products. Consumers are becomingaccustomed to high definition video in their home entertainment centersas well as high end graphic capabilities on personal computers. Severalaudio/video interface standards have been developed to link a digitalaudio/video source, such as a set-top box, DVD player, audio/videoreceiver, digital camera, game console or personal computer with anaudio/video rendering device such as a digital television, a highdefinition video display panel or computer monitor. Examples of digitalvideo interface technology available for consumer electronics compriseHigh-Definition Multimedia Interface (HDMI), Display Port, Digital VideoInterface (DVI) and Unified Display Interface (UDI) for example. Theseaudio/video interfaces may each comprise unique physical interfaces andcommunication protocols.

As high data rates are required, new transmission technologies enablehigher transmission rates over copper cabling infrastructures. Variousefforts exist in this regard, including technologies that enabletransmission rates that may even reach 100 Gigabit-per-second (Gbps)data rates over existing cabling. For example, the IEEE 802.3 standarddefines the (Medium Access Control) MAC interface and physical layer(PHY) for Ethernet connections at 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbpsdata rates over twisted-pair copper cabling 100 m in length. With each10× rate increase more sophisticated signal processing is required tomaintain the 100 m standard cable range. Non-standard transmission ratescomprise 2.5 Gbps as well as 5 Gbps.

The specification for 10 Gigabit-per-second (Gbps) Ethernettransmissions over twisted-pair cabling (10 GBASE-T) is intended toenable 10 Gbps connections over twisted-pair cabling at distances of upto 182 feet for existing cabling, and at distances of up to 330 feet fornew cabling, for example. To achieve full-duplex transmission at 10 Gbpsover four-pair twisted-pair copper cabling, elaborate digital signalprocessing techniques are needed to remove or reduce the effects ofsevere frequency-dependent signal attenuation, signal reflections,near-end and far-end crosstalk between the four pairs, and externalsignals coupled into the four pairs either from adjacent transmissionlinks or other external noise sources. New IEEE cabling specificationsare being considered for 40 Gbps and 100 Gbps rates.

There may be instances where the data rate required for transmission inone direction may be much higher than the data rate required fortransmission in the opposite direction, such as the delivery ofinteractive video from a central office to the consumer, for example. Inthis regard, the data rate for the transmission of video in onedirection may be much higher than the data rate required fortransmitting interactive commands in the opposite direction.

A/V Bridging (AVB) comprises a set of specifications, which defineservice classes (or AVB services) that enable the transport ofaudio/video (A/V) streams (and/or multimedia streams) across anAVB-enabled network (or AVB network) based on selected quality ofservice (QoS) descriptors. Specifications, which enable the definitionof AVB service classes, include the following.

A specification, which enables a set of AVB-enabled devices (or AVBdevices) within an AVB network to exchange timing information. Theexchange of timing information enables the devices to synchronize timingto a common system clock, which may be provided by a selected one of theAVB devices within the AVB network.

A specification, which enables an AVB destination device to register arequest for delivery of a specified AV stream from an AVB source device.In addition, an AVB source device may request reservation of networkresource, which enables the transmission of a specified AV stream. TheStream Reservation Protocol (SRP) defined within the specificationprovides a mechanism by which the AVB source device may register therequest to reserve resources within the AVB network (such as bandwidth)to enable the transmission of the specified AV stream, The MultipleMulticast Registration Protocol (MMRP) may enable an AVB destinationdevice to register the request for delivery of a specified AV stream.

A specification, which defines procedures by which AV streams aretransported across the AVB network. These procedures may include methodsfor the queuing and/or forwarding of the AV streams by individual AVBdevices within the AVB network.

A typical AVB network comprises a set of AVB devices, which arecollectively referred to as an AVB block. An AVB network may comprisewired local area networks (LANs) and/or wireless LANs (WLANs), forexample. Individual AVB devices within the AVB network may includeAVB-enabled endpoint computing devices (such as laptop computers andWLAN stations), AVB-enabled switching devices (AV switches) within LANsand AVB-enabled access points (APs) within WLANs, for example. Withinthe AVB block, AV destination devices may request AV streams from AVsource devices, which may be transported across the AVB network withinspecified latency target values as determined from the QoS descriptorsassociated with delivery of the AV stream.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with the present invention as set forth inthe remainder of the present application with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for an asymmetric PHY operation forEthernet A/V Bridging and Ethernet A/V Bridging extensions,substantially as shown in and/or described in connection with at leastone of the figures, as set forth more completely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a diagram illustrating an exemplary system for transfer ofvideo and/or audio data wherein Audio/Video Bridging (AVB) services maybe implemented via an asymmetric multi-rate Ethernet physical layer(PHY) connection, in accordance with an embodiment of the invention.

FIG. 1B is a diagram illustrating an exemplary system for transfer ofvideo, audio and/or auxiliary data via a network comprising one or moreintermediate nodes utilizing an AVB services and an asymmetricmulti-rate Ethernet physical layer (PHY) connection, in accordance withan embodiment of the invention.

FIG. 2 is a diagram illustrating exemplary processes utilized in AVBmanaged data transfers from an upstream link partner to a downstreamlink partner utilizing asymmetric Ethernet multi-rate PHY technology, inaccordance with an embodiment of the invention.

FIG. 3 is a block diagram illustrating an Ethernet system overtwisted-pair cabling link between an upstream link partner and adownstream link transmitting asymmetric data traffic with AVB services,in connection with an embodiment of the invention.

FIG. 4 is a block diagram illustrating an exemplary Ethernet transceiverarchitecture comprising an asymmetric multi-rate PHY, in accordance withan embodiment of the invention.

FIG. 5 is a block diagram illustrating ECHO, NEXT, and FEXT channelconditions in an Ethernet system, in accordance with an embodiment ofthe invention.

FIG. 6 is a block diagram illustrating exemplary 10Gigabit signalprocessing operations for received signals in an Ethernet systemutilized for asymmetric data traffic, in accordance with an embodimentof the invention.

FIG. 7 is a block diagram of a multi-rate Ethernet system for asymmetricdata traffic that utilizes 10 Gigabit signal processing resources in afour-pair extended range mode, in accordance with an embodiment of theinvention.

FIG. 8 is a block diagram of an exemplary echo canceller in an upstreamasymmetric multi-rate PHY with a 10 Gbps downstream data rate and a 1Mbps upstream data rate, in connection with an embodiment of theinvention.

FIG. 9 is a block diagram of a multi-rate Ethernet system for asymmetricdata traffic that utilizes 10 Gigabit signal processing resources in anasymmetric mode over fewer than 4 twisted pairs of wires, in accordancewith an embodiment of the invention.

FIG. 10 is a flow diagram illustrating exemplary steps in communicationrate reduction in Ethernet systems that utilize asymmetric multi-ratePHYs, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor transmitting and receiving Audio/Video Bridging (AVB) streamsbetween devices wherein each device may comprise a Media Access Control(MAC) layer supporting AVB services and an asymmetric multi-rateEthernet physical layer (PHY). The MAC layer functions that support AVBmay enable the end-to-end transport of Ethernet frames based onspecified latency targets by initiating admission control procedures.The asymmetrical multi-rate Ethernet PHY functions may enabletransmission of AVB streams at a first data rate and reception of AVBstreams at a second data rate on each of an upstream device and a downstream device. The first data rate may be different from the second datarate. For example, the upstream device may transmit high bandwidthaudio, video (A/V) and/or auxiliary data signals at a first data rateand receive lower bandwidth auxiliary data signals at a second data ratethat may be a slower standard data rate. Auxiliary data may comprise forexample control and/or configuration signals, input from peripheraldevices such as keyboards and/or mice, and/or information utilized forsecurity operations such as encryption keys for example.Notwithstanding, the downstream device may transmit the lower bandwidthauxiliary data signals at the first data rate and receive high bandwidthA/V and/or auxiliary signals at the second data rate.

Although AVB services may support video, audio and/or auxiliary datatransfers, the invention is not limited in this regard. For example, theAVB services may be utilized to support any latency or bandwidthsensitive data.

In various embodiments of the invention, each of the first data rateand/or the second data rate signals may be apportioned evenly orunevenly among one or more twisted-pair wire in copper cabling Ethernetcommunication links. In this regard, each of the twisted pair links maysupport a data rate reduced from the first data rate or a data ratereduced from the second data rate. The reduced communication rates maybe achieved by reducing the symbol rate provided to the asymmetricEthernet multi-rate PHY. The asymmetric Ethernet multi-rate PHY maysupport signal-processing operations on its high communication rateoperations, such as echo cancellation, cross talk cancellation and/orequalization that may be applied to the lower communication rate signalsto enable range extension. Reducing the communication rate may enableutilizing cabling with greater insertion loss than those used for astandard connection distance.

FIG. 1A is a diagram illustrating an exemplary system for transferring,video, audio (A/V) and/or auxiliary data via a network utilizingAudio/Video Bridging (AVB) by a media access control (MAC) layer anasymmetric multi-rate Ethernet physical layer (PHY) connection, inaccordance with an embodiment of the invention. Referring to FIG. 1A,there is shown a server 122, a video display panel 126, speakers 128 aand 128 b, a plurality of Ethernet links 132 a and 132 b, a network 110,a digital musical instrument 123, speakers 125 and Ethernet links 133 aand 133 b.

The server 122 may be communicatively coupled with the video displaypanel 126 and speakers 128 a and 128 b via the Ethernet links 132 a and132 b and the network 110. The server 122 may transfer high bandwidthdata, for example, A/V data to the video display panel 126 and speakers128 a and 128 b. The server 122 may comprise an Ethernet media accesscontrol (MAC) layer for encapsulating data in Ethernet frames andtransmission control to the video display panel 126 and speakers 128 aand 128 b via the Ethernet links 132 a, 132 b and the network 110. Inthis regard, the MAC layer may support Audio/Video Bridging (AVB)services wherein end to end quality of service operations may be enabledaccording to traffic class designations associated with Ethernet frames.In addition, the server 122 may comprise and asymmetric multi-rateEthernet PHY transceiver. In other embodiments of the invention, theserver 122 may be, for example, a personal computer, a DVD player, avideo game console and/or an A/V receiver. The invention is not limitedto these examples and may comprise any suitable source of data.

The video display panel 126 and speakers 128 a and 128 b may comprisesuitable logic, circuitry and or code to exchange information with theserver 122 via the Ethernet connections 132 a and 132 b and the network110. Tasks performed by the video display panel 126 and speakers 128 aand 128 b may comprise reception of Ethernet frames via the Ethernetlink 132 b, determination that the Ethernet frames may compriseencapsulated A/V content that may be native video or A/V data formattedby a display interface for example HDMI, Display Port or DVI andextraction of the formatted or native A/V content from the Ethernetframes and rendering the A/V content. In this regard, if the A/V data isformatted, the A/V data may comprise instructions for rendering theformatted video data on the video display panel 126 and speakers 128 aand 128 b, for example. Thus, various embodiments of the invention mayenable the video display panel 126 and speakers 128 a and 128 b to be a“thin client” device that may not comprise high performance hardwareand/or software capabilities utilized in the generation of multimediacontent for high performance video and/or graphics applications. This inturn may enable the rendering of high performance video and/or graphicson the remote video display panel 126 and speakers 128 a and 128 b.

In addition, the video display panel 126 and speakers 128 a and 128 bmay comprise an Ethernet MAC layer for encapsulating data in Ethernetframes and for administration of transmissions to and receptions fromthe server 122 via Ethernet links 132 a, 132 b and the network 110. Inthis regard, the MAC layer may support Audio/Video Bridging (AVB)services wherein end to end quality of service operations may be appliedaccording to traffic class designations associated with Ethernet frames.Also, the video display panel 126 and speakers 128 a and 128 b maycomprise an asymmetric multi-rate Ethernet PHY transceiver linked viathe network 110 and Ethernet links 132 a and 132 b. Moreover, the videodisplay panel 126 and speakers 128 a and 128 b may comprise suitablelogic, circuitry and or code to process received A/V and/or auxiliarydata from the server 122 for rendering.

The video display panel 126 and speakers 128 a and 128 b may comprisesuitable logic circuitry, and/or code that may enable exchanging A/V andor auxiliary data with the server 122 via a Ethernet links 132 a, 132 band the network 110 as well as rendering the A/V content. In thisregard, the received data may comprise instructions and/or controlinformation that be utilized for the rendering processes.

The Ethernet links 132 a, 132 b, 133 a and 133 b may comprise suitablelogic, circuitry and/or code to support asymmetric multi-rate EthernetPHY operations. Exemplary Ethernet links may comprise category 5category 5e, category 6, category 6a, category 7 or better cabling forexample. However, the invention is not limited in this regard, forexample, category 3-type 2 cables may be utilized as well. Moreover,cables may be shielded or unshielded. The Ethernet links 132 a, 132 b,133 a and 133 b may be enabled to handle communications administered byquality of service mechanisms for example A/V Bridging. The Ethernetlink 132 a may be communicatively coupled with the server 122 and thenetwork 110 that may comprise, for example, an Ethernet bridge. Inaddition, the Ethernet link 132 b may be communicatively coupled withthe network 110 and one or more of the video display panel 126 andspeakers 128 a and 128 b. The server 122 and the one or more videodisplay panel 126 and speakers 128 a and 128 b may be enabled toexchange A/V and/or auxiliary data via the Ethernet links 132 a and 132b and the network 110.

The network 110 may comprise suitable logic, circuitry and or code totransfer data between one or more data source devices for example theserver 122 and one or more data destination devices for example thevideo display panel 126 and speakers 128 a and 128 b. The network 110may comprise one or more Ethernet bridges and may operate according toIEEE 802.1D standards for example. The network 110 may support AVBservices and one or more of symmetric Ethernet PHY operations and/orasymmetric multi-rate Ethernet PHY operations according to an embodimentof the invention. The network 110 may be communicatively coupled withthe server 122, the video display panel 126 and speakers 128 a and 128b, the digital musical instrument 123 and the speakers 125 via theEthernet links 132 a, 132 b, 133 a and 133 b respectively.

The digital musical instrument 123 may comprise suitable logic,circuitry and/or code to transfer audio data at a high data rate to, forexample, the speakers 125 via the network 110 and the Ethernet links 133a and 133 b utilizing AVB services. In this regard, digital musicalinstrument 123 may comprise an Ethernet media access control (MAC) layerfor encapsulating data in Ethernet frames and providing transmissioncontrol to the speakers 125. In addition, the MAC layer within thedigital musical instrument 123 may support Audio/Video Bridging (AVB)services wherein end to end quality of service operations may be enabledaccording to traffic class designations associated with Ethernet frames.Moreover, the digital musical instrument 123 may comprise an asymmetricmulti-rate Ethernet PHY transceiver wherein high data rate audio may betransmitted to the network 110 and lower data rate signals comprisingfor example control, configuration and/or security data, may be receivedfrom the network 110 via the Ethernet link 133 a. Accordingly, thespeaker system 125 may receive the high data rate audio signals from thenetwork 110 and transmit the lower data rate signals to the network 110via the Ethernet link 133 b.

In operation, the server 122 may comprise A/V and/or auxiliary data thatmay enable rendering of the A/V data on the video display panel 126 andspeakers 128 a and 128 b. A user may request a transfer of A/V data fromthe upstream server 122 via the network 110 to the down stream videodisplay panel 126 and speakers 128 a and 128 b. The server 122 mayprocess the A/V data prior to transmission. For example, the A/V datamay comprise native video or may be formatted by a display interlaceprocess such as HDMI, Display Port or DVI along with auxiliary data forexample. A MAC layer within the server 122 may convert the A/V and/orauxiliary data to Ethernet frames and assign the Ethernet frames atraffic class. The MAC layer within the server 122 may utilizeAudio/Video Bridging (AVB) to enable timely transmissions of theEthernet frames to the video display panel 126 and speakers 128 a and128 b within specified latency constraints.

The asymmetric multi-rate Ethernet PHY transceiver may process theEthernet frames and transmit them via the Ethernet link 132 a to thenetwork 110. The network 110 may receive the one or more Ethernet framesvia a symmetric Ethernet PHY or an asymmetric multi-rate Ethernet PHYtransceiver. A MAC layer within the network 110 may administertransmission of the Ethernet frames to the video display panel 126 andspeakers 128 a and 128 b according to the specified latency constraintsvia a symmetric Ethernet PHY or an asymmetric multi-rate Ethernet PHY.In this regard, the video display panel 126 and speakers 128 a and 128 bmay perform signal processing operations on the received Ethernet frameswithin an asymmetric multi-rate Ethernet PHY transceiver. A MAC layerwithin the video display panel 126 and speakers 128 a and 128 b mayconvert the Ethernet frames back to the video interface format such asHDMI, Display Port, DVI or native video and the A/V data may berendered.

Although the A/V and/or auxiliary data may be processed by the server122 via a display interface, for example HDMI, Display Port or DVI, suchthat it may be intended for point to point data exchange and may not benetwork aware nor comprise a means of network identification (forexample a network destination address), the A/V and/or auxiliary datamay be encapsulated in Ethernet frames at, for example, the server 122and transported via Ethernet links 132 a and 132 b and the network 110.The encapsulated A/V and/or auxiliary data may be decapsulated at adestination device such as the video display panel 126 and speakers 128a and 128 b. Accordingly, in various embodiments of the invention, thepoint to point oriented display interface traffic may be received by thevideo display panel 126 and speakers 128 a and 128 b as though the videodisplay panel 126 and speakers 128 a and 128 b were directly attached tothe server 122.

In addition, the video display panel 126 and speakers 128 a and 128 bmay transmit lower bandwidth data upstream. The lower bandwidth data maycomprise service requests, control information and/or security operationcommunications for example. The invention is not limited in this regardand any other suitable lower bandwidth data may be communicated on theupstream links.

The upstream lower bandwidth data may be passed to the MAC layer of thevideo display panel 126 and speakers 128 a and 128 b that may generateone or more Ethernet frames and schedule transmission of the one or moreEthernet frames to the network 110. The asymmetric multi-rate EthernetPHY transceiver within the video display panel 126 and speakers 128 aand 128 b may process the one or more Ethernet frames and transmit themvia the Ethernet link 132 b to the network 110. The network 110 mayreceive the one or more Ethernet frames from the video display panel 126and speakers 128 a and 128 b via a symmetric Ethernet PHY or anasymmetric multi-rate Ethernet PHY transceiver. A MAC layer within thenetwork 110 may schedule transmission of the one or more Ethernet framesto the server 122 via a symmetric Ethernet PHY or an asymmetricmulti-rate Ethernet PHY transceiver in the network 110. In this regard,the server 122 may receive the Ethernet frames and perform signalprocessing operations on them within the symmetric or asymmetricmulti-rate Ethernet PHY transceiver. The MAC layer within the server 122may decapsulate the lower bandwidth data and the data may be processedfor operations residing within the server 122.

FIG. 1B is a block diagram illustrating an exemplary network thatsupports Audio/Video Bridging (AVB) and asymmetrical multi-rate EthernetPHY communications in accordance with an embodiment of the invention.Referring to FIG. 1B, there is shown an AVB server 122, a plurality ofAVB Ethernet bridges 110 a and 110 b, a plurality of AVB display panels126 a, 126 b, 126 c and 126 d and a plurality of Ethernet links 132 a,132 b, 132 c, 132 d, 132 f and 132 g.

The AVB server 122 in FIG. 1B may be similar or substantially the sameas the server 122 in FIG. 1A. The AVB display panels 126 a, 126 b, 126 cand 126 d may each be similar to or substantially the same as the videodisplay panel 126 and speakers 128 a and 128 b shown in FIG. 1A. TheEthernet links 132 a, 132 b, 132 c, 132 d, 132 f and 132 g may besimilar to or substantially the same as the Ethernet links 132 a, 132 b,133 a and 133 b in FIG. 1A.

The AVB bridges 110 a and 110 b may comprise suitable logic, circuitryand/or code that may enable AVB services within an AVB network forexample, a local area network (LAN). The AVB bridges 110 a and 110 b maybe configured to transmit and/or receive Ethernet frames via Ethernetlinks wherein the Ethernet links may be coupled to distinct ports withinthe AVB bridges 110 a and 110 b. For example, the AVB bridge 110 a mayreceive and/or transmit Ethernet frames via Ethernet links 132 a, 132 b,132 c and 132 d. The AVB bridge 110 a may communicate with the AVBbridge 110 b via Ethernet link 132 d. The AVB bridge 110 a maycommunicate with the AVB display panel 126 a and 126 b via Ethernetlinks 132 b and 132 c, respectively, as well as the AVB server 122 viathe Ethernet link 132 a. Moreover, the AVB Ethernet bridges 110 a and110 b may comprise Ethernet PHY transceivers that may be enabled tohandle symmetric and/or asymmetric multi-rate traffic. In addition, theAVB bridge 110 b may be coupled to distinct ports within the AVB displaypanels 126 c and 126 d and may be enabled to transmit and/or receiveEthernet frames with AVB display panels 126 c and 126 d via Ethernetlinks 132 f and 132 g respectively.

Notwithstanding, one or more of the AVB server 122, AVB display panels126 a, 126 b, 126 c and 126 d and AVB bridges 110 a and 110 b maycomprise asymmetric multi-rate Ethernet PHY transceivers wherein highbandwidth data may be transmitted downstream from the server 122 to oneor more of the display panels 126 a, 126 b, 126 c and 126 d while lowerbandwidth data for example auxiliary data may be transmitted upstreamfrom one or more of the display panels 126 a, 126 b, 126 c and 126 d tothe server 122.

In operation, the AVB server 122 may be enabled to exchange AVB datastreams with one or more AVB display panels 126 a, 126 b, 126 c and 126d via the Ethernet links 132 a, 132 b, 132 c, 132 d, 132 f, 132 g andAVB brides 110 a and 110 b and wherein one or more of the AVB devicesmay comprise asymmetric multi-rate Ethernet PHY transceivers. Forexample, the AVB server 122 may exchange AVB data with one AVB displaypanel and/or may communicate and multi-cast transmissions with aplurality of participating AVB display panels.

In various embodiments of the invention, AVB devices comprising the AVBserver 122, AVB display panels 126 a, 126 b, 126 c and 126 d and/or AVBbridges 110 a and 110 b may associate with each other based on anexchange of logical link discovery protocol (LLDP) messages, which maybe periodically transmitted from the respective devices. The LLDPmessages describe the attributes of the device that transmits themessage. For example, the AVB server 122 may transmit LLDP messages,which describe the attributes of the AVB server 122 via Ethernet link132 a. Similarly, the AVB bridge 110 a may transmit LLDP messages, whichdescribe the attributes of the AVB bridge 110 a via Ethernet links 132a, 132 b, 132 c and 132 d. In a substantially similar manner, the bridge110 b and AVB display panels 126 a, 126 b, 126 c and 126 d may transmitone or more LLDP messages that may describe their respective attributesvia their respective coupled Ethernet links.

The LLDP messages may comprise a “time-synch” capable attribute and anAVB-capable attribute. An AVB enabled device such as the server 122, AVBdisplay panels 126 a, 126 b, 126 c and 126 d and bridgees 110 a and 110b, that receives an LLDP message, that may comprise thetime-synch-capable attribute and AVB-capable attribute via a port, maylabel the port to be an “AVB” port. Labeling the port to be an AVB portmay enable the AV device to utilize AVB services. The AVB devices, whichmay be reachable via the port, may be referred to as “participating”devices. The participating devices may utilize AVB services and may beenabled to transmit AVB streams among the participating AVB device.

Prior to transmitting the AVB data streams, a source of the transmissionfor example the AVB server 122 may propagate requests for reservation ofresources among the participating AVB devices. The reservation messagemay comprise a set of reservation parameters, for example, QoSdescriptors based on a traffic class designation. AVB devices enabled toreceive the transmitted AVB data streams, for example, one or more ofthe AVB display panels 126 a, 126 b, 126 c and 126 d may registerrequests for delivery of the AVB streams. The invention is not limitedin this regard, for example, one or more AVB display panels 126 a, 126b, 126 c and 126 d may be the source of an auxiliary data streamtransmission and may propagate a request for reservation of resourceswhile the server 122 and/or another participating device may register arequest for delivery of the auxiliary data stream.

Ethernet frames may comprise time stamps which may enable the AVBnetwork to transport the Ethernet frames along an end to end path from adata source to a data destination such that the latency of the transportalong the path may be within specified latency targets or desiredvalues. For example, the path from the AVB server 122 to the AVB displaypanel 126 c may comprise the Ethernet link 132 a, the AVB bridge 110 a,the Ethernet link 132 d, the AVB bridge 110 b and the Ethernet link 132f. Along the path, the AVB bridge 110 a may utilize the time stamps todetermine a time interval for queuing and forwarding of Ethernet framesreceived via the interface 132 a and forwarded via the interface 132 d.Similarly, the AVB bridge 110 b may utilize the time stamps to determinea time interval for the queuing and forwarding of Ethernet framesreceived via the Ethernet interface 132 d and forwarded via theinterface 132 f.

FIG. 2 is a diagram illustrating exemplary transfer of video, audioand/or auxiliary data traffic across a network utilizing Audio/VideoBridging (AVB), in accordance with an embodiment of the invention.Referring to FIG. 2, there is shown a data source computing device 288comprising a digital video/audio/auxiliary data block 202, a MAC clientblock 214, a timing shim block 216, an Ethernet MAC block 220 and anasymmetric multi-rate Ethernet PHY block 224. In addition, an AVB bridge110 may comprise a symmetric Ethernet PHY and/or an asymmetricmulti-rate Ethernet PHY 228, an Ethernet MAC block 232 a, an EthernetMAC block 232 b and a symmetric Ethernet PHY and/or an asymmetricmulti-rate Ethernet PHY 236. Moreover, a data destination computingdevice 290 may comprise an asymmetric multi-rate Ethernet PHY 240 and anEthernet MAC 244 with high layer processes.

The data source computing device 288 may comprise suitable logic,circuitry and/or code that may enable handling video, audio and/orauxiliary data. In addition, the data source computing device 288 mayutilize Audio/Video Bridging (AVB) services. The data source computingdevice 288 may be an upstream link partner wherein an asymmetricalmulti-rate Ethernet PHY transceiver 224 may be configured to transmithigh frequency data for example video, audio and/or auxiliary data andreceive lower frequency auxiliary data. The data source computing device288 may be similar or substantially the same as the server 122 describedin FIGS. 1A and 1B for example.

Moreover the data destination computing device 290 may comprise suitablelogic, circuitry and/or code that may enable handling video, audioand/or auxiliary data. In addition, the data destination computingdevice 290 may utilize Audio Video Bridging (AVB) services. The datadestination computing device 290 may be a downstream link partnerwherein an asymmetrical multi-rate Ethernet PHY transceiver 240 withinthe data destination device 290 may be configured to receive highfrequency data for example video, audio and/or auxiliary data andtransmit lower frequency auxiliary data. The data destination computingdevice 290 may be similar or substantially the same as the video displaypanel 126 and speakers 128 a and 128 b described in FIG. 1A or displaypanels 126 a, 126 b, 126 c and 126 d in FIG. 1B for example.

The AVB bridge 110 may be similar or substantially the same as thebridges 110 a and/or 110 b in FIGS. 1A and/or 113.

The digital video, audio and/or auxiliary data 202 may be stored inmemory and/or may be generated by one or more applications that may beexecuting within the data source computing device 288. The digitalvideo, audio and/or auxiliary data 202 may be encrypted or unencryptedand may be compressed or uncompressed. The digital video, audio and/orauxiliary data 202 may be passed to the MAC client 214.

In another embodiment of the invention, the digital video, audio and/orauxiliary data 202 may be passed to a display interface encapsulationprocess wherein the digital video, audio and/or auxiliary data 202 maybe encapsulated into a format such as HDMI, Display Port or DVI forexample. The display interface encapsulated digital video, audio and/orauxiliary data 202 may comprise instructions to enable rendering of thedata on the data destination computing device 290. In addition, thedigital video, audio and/or auxiliary data 202 may be encapsulated to anEthernet payload format. Accordingly, Ethernet payloads may comprisecompressed, uncompressed, packetized, unpacketized, encapsulated,decapsulated or otherwise processed data so as to be formatted as one ormore video or multimedia streams. For example, one or more of IPdatagrams, HDMI datastreams, DVI datastreams, DisplayPort datastreams,raw video, and/or raw audio/video may be converted to an Ethernetpayload. The Ethernet payload may be passed to the MAC client block 214.

The MAC client block 214 may comprise suitable logic, circuitry, and/orcode that may enable reception of digital video, audio and/or auxiliarydata 202 and/or the Ethernet payloads and may enable encapsulation ofthe digital video, audio and/or auxiliary data 202 and/or the Ethernetpayloads in one or more Ethernet frames. The Ethernet frames may bepassed to the timing shim 216.

The timing shim 216 may comprise suitable logic, circuitry and/or codethat may enable reception of Ethernet frames the MAC client block 214.The timing shim 216 may append time synchronization information, such asa time stamp, to the Ethernet frames. The timing shim 216 may, forexample, append a time stamp when an Ethertype field within the Ethernetframe indicates that the Ethernet frame is enabled to utilize AVBcapabilities for transport across a network. The timing shim 216 maypass the appended Ethernet frames to the Ethernet MAC 220.

The Ethernet MAC 220 may comprise suitable logic, circuitry, and or codethat may enable addressing and/or access control to a network and mayenable the transmission of the Ethernet frames via a network. In thisregard, the Ethernet MAC 220 may be enabled to buffer, prioritize, orotherwise coordinate the transmission and/or reception of data via theasymmetrical multi-rate Ethernet PHY 224. The Ethernet MAC 220 may beenabled to perform additional packetization, depacketization,encapsulation, and decapsualtion of data. The Ethernet MAC 220 mayenable generation of header information within the Ethernet frames,which enable the utilization of AVB services within a network fortransport of the Ethernet frames. The Ethernet MAC 220 may also enabletraffic shaping of transmitted Ethernet frames by determining timeinstants at which Ethernet frames may be transmitted to a network. TheEthernet MAC 220 may also enable generation of header information withinthe Ethernet frames, which utilize conventional Ethernet services. Theconventional Ethernet services may not utilize traffic shaping and/orAVB services for example. The Ethernet MAC 220 may pass the Ethernetframes and/or link management control signals to the asymmetricmulti-rate Ethernet PHY 224.

The asymmetric multi-rate Ethernet PHY 224 may process the Ethernetframes and enable transport of the Ethernet frames to the AVB bridge 110utilizing AVB services. The asymmetric multi-rate Ethernet PHY 224 maybe enabled to convert between digital values and analog symbolsimpressed on the physical medium.

The asymmetric multi-rate Ethernet PHY 228 may be configured to receiveEthernet frames from the data source computing device 288. The Ethernetbridge 110 may receive the Ethernet frames via the asymmetricalmulti-rate Ethernet PHY 228 wherein the received Ethernet signals may beprocessed by asymmetric multi-rate Ethernet PHY operations. The Ethernetframes may be passed to the Ethernet MAC 232 a.

The Ethernet MAC 232 a may enable the Ethernet bridge 110 to receive theEthernet frames from the data source computing device 288 and maydetermine that the data destination computing device 290 is thedestination for receipt of the Ethernet frames. The Ethernet MAC layer232 b may utilize time stamp information and quality of servicedescriptors to schedule the transmission of the Ethernet frames to thedata destination device 290. The MAC 232 b may pass the Ethernet framesto the asymmetric multi-rate Ethernet PHY 236, which may enabletransport of the Ethernet frames to the data destination computingdevice 290.

Within the data destination computing device 290, the asymmetricmulti-rate Ethernet PHY 240 may receive the Ethernet frames that may besubsequently sent to the Ethernet MAC 244. The Ethernet MAC 244 mayextract the Ethernet payloads and information comprised in fields of theEthernet frames as well as any information comprised within additionalencapsulation fields if present, for example, display interface fieldsand may reconstruct the digital video/audio/auxiliary data according toinformation therein. The MAC layer may determine the type of dataextracted and/or reconstructed from the frame and/or encapsulationfields and may process, store and/or forward the data accordingly. TheMAC layer may determine that data may be forwarded to higher levelapplications for rendering of the video and/or audio content.

FIG. 3 is a block diagram illustrating an Ethernet system overtwisted-pair cabling link between an upstream link partner and adownstream link partner for asymmetric data traffic supported by AudioVideo Bridging (AVB) services, in connection with an embodiment of theinvention. Referring to FIG. 3, there is shown a system 300 thatcomprises an upstream link partner 302 and a downstream link partner304. The upstream link partner 302 may comprise a host processing block306 a, a medium access control (MAC) controller 308 a, and a transceiver304 a. The downstream link partner 304 may comprise a display videoprocessing block 306 b, a MAC controller 308 b, and a transceiver 310 b.Notwithstanding, the invention is not limited in this regard.

The upstream link partner 302 and the downstream link partner 304communicate via a cable 312. The cable 312 may be a four-pair unshieldedtwisted-pair (UTP) copper cabling, for example. Certain performanceand/or specifications criteria for UTP copper cabling have beenstandardized. An exemplary Ethernet connection may comprise category 5category 5e, category 6, category 6a, category 7 or better cabling forexample. However, the invention is not limited in this regard, forexample, category 3-type 2 cables may be utilized as well. Moreover,cables may be shielded or unshielded. For example, Category 5 orCategory 5e cabling may provide the necessary performance for 10 MbpsEthernet transmissions over twisted-pair cabling (10BASE-T). In anotherexample, Category 5 cabling may provide the necessary performance for1000 Mbps, or Gbps, Ethernet transmissions over twisted-pair cabling(1000BASE-T). In some embodiments of the invention, non standard speedsfor example 2.5 Gbps and 5 Gbps may be utilized. In most instances, alower category cable may generally have a greater insertion loss than ahigher category cable.

The transceiver 310 a may comprise suitable logic, circuitry, and/orcode that may enable asymmetric Ethernet communication, such astransmission and reception of data, for example, between the upstreamlink partner 302 and the downstream link partner 304, for example. Inthis regard, the transceiver 310 a may enable transmission at a highdata rate to the downstream link partner 304 while also enablingreception at a low data rate from the downstream link partner 304.Similarly, the transceiver 310 b may comprise suitable logic, circuitry,and/or code that may enable asymmetric Ethernet communication betweenthe downstream link partner 304 and the upstream link partner 302, forexample. In this regard, the transceiver 310 b may enable transmissionat a low data rate to the upstream link partner 302 while also enablingreception at a high data rate from the upstream link partner 302.

The data transmitted and/or received by the transceivers 310 a and 310 bmay be formatted in a manner that may be compliant with the well-knownOSI protocol standard, for example. The OSI model partitions operabilityand functionality into seven distinct and hierarchical layers.Generally, each layer in the OSI model is structured so that it mayprovide a service to the immediately higher interfacing layer. Forexample, layer 1, or physical (PHY) layer, may provide services to layer2 and layer 2 may provide services to layer 3. In this regard, thetransceiver 310 a may enable PHY layer operations that are utilized forasymmetric data communication with the downstream link partner 304.Moreover, the transceiver 310 a may enable PHY layer operations that areutilized for asymmetric data communication with the upstream linkpartner 302.

The transceivers 310 a and 310 b may enable asymmetric multi-ratecommunications. In this regard, the data rate in the upstream and/or thedownstream direction may be <10 Mbps, 10 Mbps, 100 Mbps, 1000 Mbps (or 1Gbps) and/or 10 Gbps, for example. The transceivers 310 a and 310 b maysupport standard-based asymmetric data rates and/or non-standardasymmetric data rates. The transceivers 310 a and 310 b may utilizemultilevel signaling in their operation. In this regard, thetransceivers 310 a and 310 b may utilize pulse amplitude modulation(PAM) with various levels to represent the various symbols to betransmitted. For example, for 1000 Mbps Ethernet applications, a PAM5transmission scheme may be utilized in each twisted-pair wire, wherePAM5 refers to PAM with five levels {−2, −1, 0, 1, 2}. In anotherexemplary embodiment of the invention, for 10 Gbps Ethernetapplications, a PAM 16 scheme may be utilized in each twisted-pair wirewith levels {−15, −13, −11, −9, −7, −5, −3, −1, 1, 3, 5, 7, 9, 11, 13,15} where two successive PAM 16 symbols are used to define a 128 point,two dimensional constellation referred to in the IEEE 802.3 standard as128 Double Square (DSQ).

The transceivers 310 a and 310 b may be configured to handle all thephysical layer requirements, which may include, but are not limited to,packetization, data transfer and serialization/deserialization (SERDES),in instances where such an operation is required. Data packets receivedby the transceivers 310 a and 310 b from MAC controllers 308 a and 308b, respectively, may include data and header information for each of theabove six functional layers. The transceivers 310 a and 310 b may beconfigured to encode data packets that are to be transmitted over thecable 312 and/or to decode data packets received from the cable 312.

The MAC controller 308 a may comprise suitable logic, circuitry, and/orcode that may enable handling of data link layer, layer 2, operabilityand/or functionality in the upstream link partner 302. Similarly, theMAC controller 308 b may comprise suitable logic, circuitry, and/or codethat may enable handling of layer 2 operability and/or functionality inthe downstream link partner 304. The MAC controllers 308 a and 308 b maybe configured to implement Ethernet protocols, such as those based onthe IEEE 802.3 standard, for example. In various embodiments of theinvention, one or more nodes, for example one or more Ethernet bridges,may be communicatively coupled to the upstream link partner 302 and thedownstream link partner 304 such that data streams may be transportedbetween the link partners via the one or more of the nodes. In thisregard, Audio/Video Bridging protocol such as IEEE 802.1AS may beutilized to synchronize the upstream link partner 302 and the downstreamlink partner 304. Accordingly, an Audio/Video Bridging protocol such asIEEE 802.1Qat may be utilized to reserve resources for the data streams.In this regard, nodes comprised within the reserved path may implementIEEE 802.1Qav to govern forwarding and queuing of time sensitive data.Notwithstanding, the invention is not limited in this regard.

The MAC controller 308 a may communicate with the transceiver 310 a viaan interface 314 a and with the host processing block 306 a via a buscontroller interface 316 a. The MAC controller 308 b may communicatewith the transceiver 310 b via an interface 314 b and with the displayvideo processing block 306 b via a bus controller interface 316 b. Theinterfaces 314 a and 314 b correspond to Ethernet interfaces thatcomprise protocol and/or link management control signals. The interfaces314 a and 314 b may be multi-rate interfaces. The bus controllerinterfaces 316 a and 316 b may correspond to PCI or PCI-X interfaces.Notwithstanding, the invention is not limited in this regard.

The host processing block 306 a and the display video processing block306 b may comprise suitable logic, circuitry and/or code to enablegraphics processing and/or rendering operations. The host processingblock 306 a and/or the display video processing block 306 b may comprisededicated graphics processors and/or dedicated graphics renderingdevices. The host processing block 306 a and the display videoprocessing block 306 b may be communicatively coupled with the MAC 308 aand the MAC 308 b respectively via the bus controller interfaces 316 aand 316 b respectively.

In the embodiment of the invention illustrated in FIG. 3, the hostprocessing block 306 a and the display video processing block 306 b mayrepresent layer 3 and above, the MAC controllers 308 a and 308 b mayrepresent layer 2 and above and the transceivers 310 a and 310 b mayrepresent the operability and/or functionality of layer 1 or the PHYlayer. In this regard, the host processing block 306 a and the displayvideo processing block 306 b may comprise suitable logic, circuitry,and/or code that may enable operability and/or functionality of the fivehighest functional layers for data packets that are to be transmittedover the cable 312. Since each layer in the OSI model provides a serviceto the immediately higher interfacing layer, the MAC controllers 308 aand 308 b may provide the necessary services to the host processingblock 306 a and the display video processing block 306 b to ensure thatdata are suitably formatted and communicated to the transceivers 310 aand 310 b. During transmission, each layer may add its own header to thedata passed on from the interfacing layer above it. However, duringreception, a compatible device having a similar OSI stack may strip offthe headers as the message passes from the lower layers up to the higherlayers.

FIG. 4 is a block diagram illustrating an exemplary Ethernet transceiverarchitecture comprising an asymmetric multi-rate PHY, in accordance withan embodiment of the invention. Referring to FIG. 4, there is shown alink partner 400 that may comprise a transceiver 402, a MAC controller404, a host processing block 406, an interface 408, and a bus controllerinterface 410.

The transceiver 402 may be an integrated device that comprises anasymmetric multi-rate PHY block 412, a plurality of transmitters 414 a,414 c, 414 e, and 414 g, a plurality of receivers 414 b, 414 d, 414 f,and 414 h, a memory 416, and a memory interface 418. The operation ofthe transceiver 402 may be the same as or substantially similar to thetransceivers 310 a and 310 b as described in FIG. 3. For example, whenthe transceiver 402 is utilized in an upstream link partner, thetransceiver 402 may enable a high rate for data transmission and a lowrate for data reception. In another example, when the transceiver 402 isutilized in a downstream link partner, the transceiver 402 may enable alow rate for data transmission and a high rate for data reception. Inthis regard, the transceiver 402 may provide layer 1 or PHY layeroperability and/or functionality that enables asymmetric data traffic.

Similarly, the operation of the MAC controller 404, the host processingblock 406, the interface 408, and the bus controller 410 may be the sameas or substantially similar to the respective MAC controllers 308 a and308 b, the host processing block 306 a and the display video processingblock 306 b, interfaces 314 a and 314 b, and bus controller interfaces316 a and 316 b as disclosed in FIG. 3. In this regard, the MACcontroller 404, the host processing block 406, the interface 408, andthe bus controller 410 may enable different data transmission and/ordata reception rates when implemented in an upstream link partner or adownstream link partner. The MAC controller 404 may comprise amulti-rate interface 404 a that may comprise suitable logic, circuitry,and/or code to enable communication with the transceiver 402 at aplurality of data rates via the interface 408.

The asymmetric multi-rate PHY block 412 in the transceiver 402 maycomprise suitable logic, circuitry, and/or code that may enableoperability and/or functionality of PHY layer requirements forasymmetric data traffic. The asymmetric multi-rate PHY block 412 maycommunicate with the MAC controller 404 via the interface 408. In oneaspect of the invention, the interface 408 may be configured to utilizea plurality of serial data lanes for receiving data from the asymmetricmulti-rate PHY block 412 and/or for transmitting data to the asymmetricmulti-rate PHY block 412, in order to achieve higher operational speedssuch as Gbps, 10 Gbps or higher speeds for example. The asymmetricmulti-rate PHY block 412 may be configured to operate in one or more ofa plurality of communication modes, where each communication modeimplements a different communication protocol. These communication modesmay include, but are not limited to, IEEE 802.3, 10 GBASE-T, othersimilar protocols and/or non-standard communication protocols thatenable asymmetric data traffic. The asymmetric multi-rate PHY block 412may be configured to operate in a particular mode of operation uponinitialization or during operation. The asymmetric multi-rate PHY block412 may also be configured to operate in an extended range mode.

The asymmetric multi-rate PHY block 412 may be coupled to memory 416through the memory interface 418, which may be implemented as a serialinterface or a bus. The memory 416 may comprise suitable logic,circuitry, and/or code that may enable storage or programming ofinformation that includes parameters and/or code that may effectuate theoperation of the asymmetric multi-rate PHY block 412. The parameters maycomprise configuration data and the code may comprise operational codesuch as software and/or firmware, but the information need not belimited in this regard. Moreover, the parameters may include adaptivefilter and/or block coefficients for use by the asymmetric multi-ratePHY block 412, for example.

The transmitters 414 a, 414 c, 414 e, and 414 g may comprise suitablelogic, circuitry, and/or code that may enable transmission of data froma transmitting link partner to a remote link partner via the cable 312in FIG. 3, for example. In this regard, when the transmitting linkpartner is an upstream link partner, the transmitters 414 a, 414 c, 414e, and 414 g may operate at a higher data rate than the data ratereceived from the downstream link partner. Similarly, when the when thetransmitting link partner is a downstream link partner, the transmitters414 a, 414 c, 414 e, and 414 g may operate at a lower data rate than thedata rate received from the upstream link partner.

The receivers 414 b, 414 d, 414 f, and 414 h may comprise suitablelogic, circuitry, and/or code that may enable receiving data from aremote link partner via the cable 312, for example. In this regard, whenthe receiving link partner is an upstream link partner, the receivers414 b, 414 d, 414 f, and 414 h may operate at a lower data rate than thedata rate transmitted to the downstream link partner. Similarly, whenthe when the receiving link partner is a downstream link partner, thereceivers 414 b, 414 d, 414 f, and 414 h may operate at a higher datarate than the data rate transmitted to the upstream link partner.

Each of the four pairs of transmitters and receivers in the transceiver402 may correspond to one of the four wire pairs in the cable 312. Forexample, transmitter 414 a and receiver 414 b may be utilized toasymmetrically communicate data with a remote link partner via the firstwire pair in the cable 312. Similarly, transmitter 414 g and receiver414 h may be utilized to asymmetrically communicate data with a remotelink partner via the fourth wire pair in the cable 312. In this regard,at least one of the four transmitter/receiver pairs may be enabled toprovide the appropriate communication rate. The above-disclosed schememay be applied to fewer, or greater, number of wires, for example.

FIG. 5 is a block diagram illustrating ECHO, NEXT, and FEXT channelconditions in an Ethernet system, in accordance with an embodiment ofthe invention. Referring to FIG. 5, there is shown an asymmetricEthernet system 500 that may comprise an upstream link partner 501 a anda downstream link partner 501 b. The upstream link partner 501 a and thedownstream link partner 501 b may asymmetrically communicate data viafour twisted-pair wires 510 in full duplex operation. Each of the fourtwisted-pair wires 510 may support a portion of the data rates that maybe necessary to provide the aggregate upstream and downstream datatraffic. In this regard, each of the four twisted-pair wires 510 maysupport an equal or even or an unequal or uneven portion of theaggregate upstream and downstream data traffic.

The upstream link partner 501 a may comprise four hybrids 506. Eachhybrid 506 in the upstream link partner 501 a may be communicativelycoupled to a transmitter 502 a, a receiver 504 a, and to one of the fourtwisted-pair wires 510. Similarly, the downstream link partner 501 b maycomprise four hybrids 506. Each hybrid 506 in the downstream linkpartner 501 b may be communicatively coupled to a transmitter 502 b, areceiver 504 b, and to one of the four twisted-pair wires 510. Theportions of the upstream link partner 501 a and the downstream linkpartner 501 b shown in FIG. 5 may correspond to a portion of thephysical (PHY) layer operations supported by the upstream link partner501 a and by the downstream link partner 501 b respectively.

Each hybrid 506 in the upstream link partner 501 a or in the downstreamlink partner 501 b may be communicatively coupled to or comprise atransformer 508. The hybrid 506 may comprise suitable logic, circuitry,and/or code that may enable separating the transmitted and receivedsignals from a twisted-pair wire 510. The transmitters 502 a and 502 bmay comprise suitable logic, circuitry, and/or code that may enablegenerating signals to be transmitted to a link partner at the other endof the link via a hybrid 506 and a twisted-pair wire 510. In thisregard, the transmitters 502 a may operate at a higher data rate thanthe transmitters 502 b. The receivers 304 may comprise suitable logic,circuitry, and/or code that may enable processing signals received froma link partner at the other end of the link via a twisted-pair wire 510and a hybrid 506. In this regard, the receivers 504 a may operate at alower data rate than the receivers 504 b.

During operation, several conditions may occur in each of thetwisted-pair wires 510. For example, intersymbol interference (ISI) mayoccur as a result of frequency dependent wire attenuation. As shown inFIG. 5, an ECHO component may be received in a twisted-pair wire 510from an echo that results from the transmitter 502 a in the upstreamlink partner 501 a on the same twisted-pair wire 510. A near-endcrosstalk (NEXT) component may also be received in a twisted-pair wire510 from the local transmitters 502 a corresponding to the threeadjacent twisted-pair wires 510 in the upstream link partner 501 a.Moreover, a far-end crosstalk (FEXT) component may also be received in atwisted-pair wire 510 from the transmitters 502 b in the downstream linkpartner 501 b at the other end of the link. Similar conditions may alsooccur in the downstream link partner 501 b, for example.

FIG. 6A is a block diagram illustrating exemplary Gigabit signalprocessing operations for received signals in an Ethernet systemutilized for asymmetric data traffic, in accordance with an embodimentof the invention. Referring to FIG. 6A, there is shown a signalprocessing system 600 that may provide a portion of the signalprocessing performed by the physical (PHY) layer operations in anEthernet transceiver that supports asymmetric multi-rate operation. Forexample, the signal processing system 600 may be implemented in theasymmetric multi-rate PHY block 412 and/or in the receivers 414 b, 414d, 414 f, and 414 h in FIG. 4. The signal processing system 600 maycomprise an analog-to-digital converter (A/D) 602, an adaptivefeed-forward equalizer (FFE) 604, a 3 NEXT canceller 606, an adder 608,an ECHO canceller 610, and an equalizer/trellis decoder 612.

The A/D 602 may comprise suitable logic, circuitry, and/or code that mayenable converting analog signals received via a twisted-pair wire intodigital signals. The output of the A/D 602 may be communicated to theFFE 604. The FFE 604 may comprise suitable logic, circuitry, and/or codethat may enable removal of precursor ISI to make the channelminimum-phase and to whiten the noise in the channel. The 3 NEXTcanceller 606 may comprise suitable logic, circuitry, and/or code thatmay enable canceling at least a portion of the NEXT component receivedin the twisted-pair wire from the local transmitters corresponding tothe three adjacent twisted-pair wires. The ECHO canceller 610 maycomprise suitable logic, circuitry, and/or code that may enablecanceling at least a portion of the ECHO component received in thetwisted-pair wire from the local transmitter on the same twisted-pairwire.

The adder 608 may comprise suitable logic, circuitry, and/or code thatmay enable adding the output of the FFE 604, the 3 NEXT canceller 606,and/or the ECHO canceller to generate a postcursor channel impulseresponse, z_(n,1). The equalizer/trellis decoder 612 may comprisesuitable logic, circuitry and/or code that may enable equalizing the ISIthat may result from the postcursor impulse response and decoding thetrellis code. The equalizer/trellis decoder 612 may receive as inputsthe postcursor channel impulse responses, z_(n,2), z_(n,3), and z_(n,4)the corresponding to the other twisted-pair wires. The equalizer/trellisdecoder 612 may generate the detected bits that correspond to thereceived analog signal.

FIG. 6B is a block diagram illustrating exemplary separate equalizationand decoding signal processing operations, in accordance with anembodiment of the invention. Referring to FIG. 6B, there is shown theequalizer/trellis decoder 612 as described in FIG. 6A that may beimplemented as separate equalization and trellis decoding operations.The equalizer/trellis decoder 612 may comprise four decision-feedbackequalizers (DFE) 620 and a trellis-coded modulation (TCM) decoder 622.The DFE 620 may comprise suitable logic, circuitry, and/or code that mayenable removing the postcursor ISI for each twisted-pair wire. The TCMdecoder 622 may comprise suitable logic, circuitry, and/or code that mayenable executing a Viterbi algorithm on the code trellis to decode thetrellis-coded symbols. The TCM decoder 622 may be implemented using aparallel decision-feedback decoding architecture, for example. Theseparate equalization and trellis decoding approach may provide lowimplementation complexity and higher data rates, such as Gbps, forexample, may be easily achieved.

FIG. 6C is a block diagram illustrating exemplary joint equalization anddecoding signal processing operations, in accordance with an embodimentof the invention. Referring to FIG. 6C, there is shown theequalizer/trellis decoder 612 as described in FIG. 6A that may beimplemented as joint equalization and trellis decoding operations. Theequalizer/trellis decoder 612 may comprise a decision-feedback prefilter(DFP) block 650 and a look-ahead parallel decision-feedback decoder(LA-PDFD) 652. The DFP block 650 may comprise four DFPs 654, one foreach twisted-pair wire. The DFP 654 may comprise suitable logic,circuitry, and/or code that may enable shortening the postcursor channelmemory. The LA-PDFP 652 may comprise suitable logic, circuitry, and/orcode that may enable computing branch metrics in a look-ahead fashion.The training and adaptation of the channel coefficients may be utilizedto improve the performance of the equalizer/trellis decoder 612.

FIG. 6D is a block diagram illustrating exemplary 10 Gigabit signalprocessing operations for receive and transmit signals in an Ethernetsystem utilized for asymmetric data traffic, in accordance with anembodiment of the invention. Referring to FIG. 6D, there is shown asignal processing system 660 that may provide a portion of the signalprocessing performed by the physical (PHY) layer operations in anEthernet transceiver that supports asymmetric multi-rate operation. Forexample, the signal processing system 660 may be implemented in theasymmetric multi-rate PHY block 412 and/or in the receivers 414 b, 414d, 414 f, and 414 h in FIG. 4. The signal processing system 660 maycomprise an analog-to-digital converter (A/D) 662, a matrix feed-forwardequalizer (FFE) 664, NEXT cancellers 666, an adder 668, an ECHOcanceller 670, a low density parity check code (LDPC) decoder 672, anadaptive pre-filter 674, an LDPC encoder 680, a 128 Double Square (DSQ)mapper 682, a Tomlinson Harashima pre-coder (THP) 684 and a digital toanalog converter 686.

The A/D 662 may comprise suitable logic, circuitry, and/or code that mayenable converting analog signals received via a twisted-pair wire intodigital signals. The output of the A/D 662 may be communicated to thematrix FFE 664. The matrix FFE 664 may comprise suitable logic,circuitry, and/or code that may enable removal of precursor ISI to makethe channel minimum-phase and to whiten the noise in the channel. TheNEXT cancellers 666 may comprise suitable logic, circuitry, and/or codethat may enable canceling at least a portion of the NEXT componentreceived in the twisted-pair wire from the local transmitterscorresponding to the three adjacent twisted-pair wires. The ECHOcanceller 670 may comprise suitable logic, circuitry, and/or code thatmay enable canceling at least a portion of the ECHO component receivedin the twisted-pair wire from the local transmitter on the sametwisted-pair wire.

The adder 668 may comprise suitable logic, circuitry, and/or code thatmay enable adding the output of the matrix FFE 664, the NEXT cancellers666, and/or the ECHO canceller 670 to generate a post-cursor channelimpulse response, z_(n,1). The adaptive pre-filter 674 and the LDPCdecoder 672 may comprise suitable logic, circuitry and/or code that mayenable mitigating the ISI that may result from the post-cursor impulseresponse and, decoding low density parity check coded data. The adaptivepre-filter 674 and LDPC decoder 672 may receive as inputs thepost-cursor channel impulse responses, z_(n,2), z_(n,3), and z_(n,4)corresponding to the other twisted-pair wires. The LDPC decoder 672 maygenerate the detected bits that correspond to the received analogsignal.

Prior to an Ethernet transmission, the low density parity check code(LDPC) encoder 680 may comprise suitable logic, circuitry and/or codefor enabling error correction. The output of the LDPC encoder 680 may besent to the 128 DSQ mapper 682. The 128 DSQ mapper 682 may be utilizedin the implementation of 16 level pulse amplitude modulation 16 (PAM16)for each twisted-pair wire. The output of the 128 DSQ mapper 682 may besent to the THP 684. The THP 684 may comprise four THPs, one for eachtwisted pair. The THP 684 may comprise suitable logic, circuitry and orcode that may enable spectral shaping in the transmitter and thus reducereceiver complexity. The output of the THP 684 may be communicated tothe DAC 686. The DAC 686 may comprise suitable logic, circuitry and/orcode that may enable converting signals from digital to analog fortransmission via a twisted-pair wire cabling. The invention is notlimited with regard to any specific signal processing operations orfunctionality. Accordingly, any suitable signal processing methodsand/or system may be utilized.

FIG. 7 is a block diagram of a multi-rate Ethernet system for asymmetricdata traffic that utilizes 10 Gigabit signal processing resources in afour-pair extended range mode, in accordance with an embodiment of theinvention. Referring to FIG. 7, there is shown an asymmetric multi-rateEthernet system 700 that may comprise an upstream link partner 701 a anda downstream link partner 701 b. The upstream link partner 701 a maycorrespond to, for example, the entry DVD player in FIG. 1, while thedownstream link partner 701 b may correspond to, for example, the highdefinition video display panel 112. The asymmetric multi-rate Ethernetsystem 700 may support a plurality of asymmetric data rates or modes ofoperation over four-pair twisted-pair wire, including the ability toprovide 1 Gbps or 10 Gbps, for example as shown in FIG. 7. In anotherembodiment of the invention, the asymmetric multi-rate Ethernet system700 may operate in an extended range mode of operation that provides 10Mbps in the downstream direction and 2 Mbps in the upstream direction,for example. In this regard, the extended range operation may beachieved by utilizing the 2 Mbps and 10 Mbps lower communication datarates, that is, data rates below the 1 Gbps or 10 Gbps that may beachieved by the signal processing operations enabled in either theupstream link partner 701 a or the downstream link partner 701 b.

The upstream link partner 701 a may comprise four hybrids 506 asdescribed in FIG. 5. Notwithstanding, the invention is not so limitedand may support various implementations of a hybrid circuitry. Eachhybrid 506 in the upstream link partner 701 a may be communicativelycoupled to a transmitter 502 a, a receiver 504 a, and to one of the fourtwisted-pair wires 510 also as described in FIG. 5. Associated with eachhybrid 506 in the upstream link partner 701 a may also be an echocanceller 702 a and a subtractor 704 a. The upstream link partner 701 amay also comprise a demultiplexer (demux) 706 a, an aligner 708 a, and amultiplexer (mux) 710 a.

Similarly, the downstream link partner 701 b may comprise four hybrids506. Each hybrid 506 in the downstream link partner 701 b may becommunicatively coupled to a transmitter 502 b, a receiver 504 b, and toone of the four twisted-pair wires 510 as described in FIG. 5.Associated with each hybrid 506 in the downstream link partner 701 b arealso an echo canceller 504 b and a subtractor 506 b. The remote linkpartner 701 b may also comprise a demux 706 b, an aligner 708 b, and amux 710 b. The portions of the upstream link partner 701 a anddownstream link partner 701 b shown in FIG. 7 may correspond to aportion of the physical (PHY) layer operations supported by the upstreamlink partner 701 a and downstream link partner 701 b respectively.

The demux 706 a may comprise suitable logic, circuitry, and/or code thatmay enable separating an exemplary 10 Gbps downstream signal into four2.5 Gbps signals for transmission over the four twisted-pair wires.Similarly, the demux 706 b may comprise suitable logic, circuitry,and/or code that may enable separating an exemplary 1 Gbps upstreamsignal into four 250 Mbps signals for transmission over the fourtwisted-pair wires. The aligner 708 a may comprise suitable logic,circuitry, and/or code that may enable aligning the 250 Mbps signalsreceived from each of the four twisted-pair wires by the upstream linkpartner 701 a. Similarly, the aligner 708 b may comprise suitable logic,circuitry, and/or code that may enable aligning the 2.5 Gbps signalsreceived from each of the four twisted-pair wires by the downstream linkpartner 701 b. The mux 710 a may comprise suitable logic, circuitry,and/or code that may enable combining the aligned 250 Mbps signals fromthe aligner 708 a to generate the received 1 Gbps upstream signal.Similarly, the mux 710 b may comprise suitable logic, circuitry, and/orcode that may enable combining the aligned 2.5 Gbps signals from thealigner 708 a to generate the received 10 Gbps downstream signal.

The echo cancellers 702 a and 702 b may comprise suitable logic,circuitry, and/or code that may enable at least partial cancellation ofthe ECHO component in the corresponding signal received via thereceivers 504 a and 504 b, respectively, associated with the sametwisted-pair wire. The subtractors 704 a and 704 b may comprise suitablelogic, circuitry, and/or code that may enable cancellation of the ECHOcomponent from the received signal.

In operation, the upstream link partner 701 a may separate a 10 Gbpssignal to be transmitted into four 2.5 Gbps signals via the demux 706 a.Each signal to be transmitted is processed by a transmitter 502 a beforebeing communicated to the corresponding twisted-pair wire via a hybrid506. The four transmitted signals may arrive at the downstream linkpartner 701 b, where each of the signals may be processed by a receiver504 b before echo cancellation occurs from the operation of acorresponding echo canceller 702 b and subtractor 704 b. The fourreceived 2.5 Gbps signals may be aligned in the aligner 708 b beforebeing combined in the mux 710 b into a 10 Gbps received downstreamsignal.

Similarly, the downstream link partner 701 b may separate a 1 Gbpssignal to be transmitted into four 250 Mbps signals via the demux 706 b.Each signal to be transmitted may be processed by a transmitter 502 bbefore being communicated to the corresponding twisted-pair wire via ahybrid 506. The four transmitted signals may arrive at the upstream linkpartner 701 a, where each of the signals may be processed by a receiver504 a before echo cancellation occurs from the operation of acorresponding echo canceller 702 a and subtractor 704 a. The fourreceived 500 kbps signals may be aligned in the aligner 708 a beforebeing combined in the mux 710 a into a 1 Gbps received upstream signal.

The upstream link partner 701 a and the downstream link partner 701 bmay communicate via all four twisted-pair wires 510 in full duplexoperation to provide an aggregate of 1 Gbps for the upstream data rateand 10 Gbps for the downstream data rate. Reducing the communicationrate to 2 Mbps and 10 Mbps from, for example, 100 Mbps or higher, whileutilizing the higher communication rate PHY layer signal processingoperations, may enable extending the range, that is, extending thestandard length, of the twisted-pair wires 510. In this regard, theasymmetric multi-rate operations of the upstream link partner 701 a anda downstream link partner 701 b may support Gigabit PHY layer operationsthat may utilize multi-level signaling to transmit multiple bits perclock interval. PAM-5 may be used to transmit 2 bits per symbol andreduce the symbol rate to carry on each twisted-pair wire 510. In thisregard, multi-level signaling may be applied at 100 Mbps, 10 Mbps, or<10 Mbps rates, that is, at lower communication rates, to permitoperation at reduced symbol rates. For example, 25 Mbps may be carriedon a single twisted-pair wire at a 12.5 Msps symbol rate. Reducing thesymbol rate enables transmission over longer cable ranges. The signalprocessing operations available in a Gigabit PHY layer may support 2, 3,4, or 5 levels of signaling with no increase in complexity, for example.

Reducing the communication rate may also enable utilizing cabling withhigher insertion loss while maintaining the same standard length. Forexample, for Gigabit operations, a Category 5 or Category 5e cable maybe utilized. Reducing the communication rate in one direction in theasymmetric data traffic to 100 Mbps, for example, may enable utilizingcabling with higher insertion loss than a Category 5 or Category 5ecabling while maintaining the 100 m length requirement under the IEEE802.3 standard. The insertion loss of a twisted-pair wire cableincreases as the square root of frequency. Insertion loss, in dB, isdirectly proportional to cable length. Applying Gigabit signalprocessing operation at 100 Mbps data rate may increase the cable range.NEXT cancellation operations also improve the SNR of each receivedsignal and may be applied at 100 Mbps and 10 Mbps rates to achievesimilar improvements in SNR and further extend the cable range at thosereduced communication rates.

The asymmetric multi-rate Ethernet system 700 need not be limited toachieving a lower communication rate in any one direction by evenlydistributing the data rate over each of the four twisted-pair wiresutilized. In another embodiment of the invention, the asymmetricmulti-rate Ethernet system 700 may achieve a lower communication rate bydistributing the data rate unevenly over each of the four twisted-pairwires utilized. For example, for a 10 Mbps downstream data rate, thefirst twisted-pair wire may support 1 Mbps, the second twisted-pair wiremay support 2 Mbps, the third twisted-pair wire may support 3 Mbps, andthe fourth twisted-pair wire may support 4 Mbps, to achieve an aggregateof 10 Mbps. A similar approach may be followed for generating anaggregate upstream data rate from unevenly distributed data rates overeach of the four twisted-pair wires utilized. In this regard, thecomponents in the upstream link partner 701 a and/or the downstream linkpartner 701 b may be adapted to handle an unevenly distributed lowercommunication rate.

FIG. 8 is a block diagram of an exemplary echo canceller in an upstreamasymmetric multi-rate PHY with a higher downstream data rate and a lowerupstream data rate, in connection with an embodiment of the invention.Referring to FIG. 8, there is shown an echo canceller 806 in a portionof an asymmetric multi-rate transceiver in an upstream link partner thatis utilized in a mode of operation that supports 10 Gbps downstream datarate and 1 Mbps upstream data rate. The echo canceller 806 may beimplemented utilizing an N tap echo canceller architecture that utilizesN/10 multipliers, for example. In this regard, the echo canceller 806may utilize a plurality of registers 810, a plurality of multipliers814, a plurality of delay taps 812, a plurality of adders 816, an outputregister 818, and a switch 820.

The echo canceller 806 may utilize a digital downstream signal that isbased on a transmission clock, F_(TX), to generate an output signal viathe switch 820 to be communicated to an adder 808, where the outputsignal is based on a receive clock, F_(RX)=F_(TX)/10. The digitaldownstream signal may be converted to an analog downstream signal by thedigital-to-analog converter (DAC) 802 for transmission via atwisted-pair copper wire 822. An analog upstream signal may be receivedby an analog-to-digital converter (ADC) 804 for conversion to a digitalupstream signal in the upstream link partner. The digital upstreamsignal and the output signal generated by the echo canceller 806 may beadded in the adder 808 to reduce the ECHO component in the receiveddigital upstream signal.

FIG. 9 is a block diagram of a multi-rate Ethernet system for asymmetricdata traffic that utilizes Gigabit signal processing resources in atwo-pair extended range mode, in accordance with an embodiment of theinvention. Referring to FIG. 9, there is shown an asymmetric multi-rateEthernet system 900 that may comprise an upstream link partner 901 a anda downstream link partner 901 b. The asymmetric multi-rate Ethernetsystem 900 may support a communication rate, for example, 10 Gbpsdownstream and 1 Gbps upstream. The asymmetric multi-rate Ethernetsystem 900 may also support other modes of operation, such as a lowerasymmetric transmission rate over two-pair twisted-pair wire. In thisregard, the asymmetric multi-rate Ethernet system 900 may support alower communication rate, such as 10 Mbps downstream data rate and 2Mbps upstream data rate, while utilizing the signal processingoperations available in the asymmetric multi-rate PHY layer forprocessing the higher communication rate, such as 1 Gbps or 10 Gbps whenavailable.

The upstream link partner 901 a and the downstream link partner 901 bmay communicate, for example, via two Category 5 twisted-pair wires 510in full duplex operation. A 5 Gbps downstream data rate at each wire mayprovide an aggregate downstream data rate of 10 Gbps and a 500 Mbpsupstream data rate at each wire may provide an aggregate upstream datarate of 1 Gbps. The upstream link partner 901 a may utilize two hybrids506 with corresponding echo canceller 902 a and a subtractor 904 a. Theupstream link partner 901 a may also utilize a demux 906 a, an aligner908 a, and a mux 910 a for transmission and reception of signals at thereduced asymmetric communication rate. Similarly, the downstream linkpartner 901 b may utilize two hybrids 506 with corresponding echocanceller 902 b and a subtractor 904 b. The downstream link partner 901b may also utilize a demux 906 b, an aligner 908 b, and a mux 910 b fortransmission and reception of signals at the reduced asymmetriccommunication rate. The two remaining twisted-pair wires may remainunused in the asymmetric multi-rate Ethernet system 900.

The asymmetric multi-rate Ethernet system 900 need not be limited toachieving a lower asymmetric communication rate by evenly distributingthe data rate over each of the two twisted-pair wires utilized. Inanother embodiment of the invention, the asymmetric multi-rate Ethernetsystem 800 may achieve a lower communication rate by distributing theupstream and downstream data rates unevenly over each of the twotwisted-pair wires utilized. For example, the first twisted-pair wiremay support a 4 Gbps downstream data rate while the second twisted-pairwire may support 6 Gbps downstream data rate, to achieve an aggregate of10 Gbps. Similarly, the first twisted-pair wire may support a 800 Mbpsupstream data rate while the second twisted-pair wire may support 200Mbps upstream data rate, to achieve an aggregate of 1 Gbps. In thisregard, the components in the upstream link partner 901 a and/or thedownstream link partner 901 b may be adapted to handle an unevenlydistributed lower communication rate with asymmetric data traffic.

FIG. 10 is a flow diagram illustrating exemplary steps in communicationrate reduction to achieve extended range in Ethernet systems thatutilize asymmetric multi-rate PHYs, in accordance with an embodiment ofthe invention. Referring to FIG. 10, there is shown a flow diagram 1000.After start step 1002, in step 1004, an asymmetric Gigabit Ethernettransceiver may be enabled. The Gigabit Ethernet transceiver may utilizean asymmetric multi-rate PHY layer that enables reducing thecommunication rate from, for example, 1 Gbps to a lower communicationrate. The lower communication rate may be a 10 Mbps downstream data rateand a 2 Mbps upstream data rate, for example, but need not be solimited. The asymmetric multi-rate PHY layer may also enable reductionof the symbol rate for the asymmetric Gigabit Ethernet transceiver. Whenreducing the communication rate or symbol rate, the asymmetricmulti-rate PHY layer enables the application of Gigabit signalprocessing operations to the reduced communication or symbol rate.

In step 1006, an extended range mode may be enabled in the asymmetricGigabit Ethernet transceiver whereby the asymmetric multi-rate PHY layerreduces the communication rate and/or the symbol rate in at least one ofthe communication directions. In step 1008, at least a portion of theasymmetric Gigabit signal processing operations available in theasymmetric multi-rate PHY layer may be utilized during the extendedrange mode to enable the use of longer cables or to enable the use ofhigher insertion loss cables at the standard length. After step 1008,the process may proceed to end step 1010.

In an embodiment of the invention, signals are communicated between anupstream link partner device 122 and a down stream link partner device126, wherein each of the link partner devices 122 and 126 comprise anasymmetric multi-rate Ethernet physical layer (PHY) to handle thecommunication. Moreover, communications between the link partners 122and 126 are handled via A/V Bridging services with quality of servicedescriptors. The signals transmitted from the upstream link partner 122to the downstream link partner 126 may comprise high bandwidthaudio/video (A/V) signals. Low bandwidth signals may be transmitted fromthe downstream link partner 126 to the upstream link partner 122.Protocol data units (PDUs) may be generated comprising one or more of atime stamp value, a traffic class designation and/or a destinationaddress.

Prior to communicating PDUs via an asymmetrical multi-rate Ethernet PHYbetween the upstream link partner 122 and the downstream link partner126, a data rate request and a reservation message for resources may begenerated based on one or more of a said time stamp value, a trafficclass designation and/or a destination address. Furthermore, an upstreamlink partner 122 or downstream link partner 126 may register for thedeliver of the PDUs via the asymmetric multi-rate Ethernet PHY. Thecommunication rate of signals may be reduced prior to distribution ofthe signals among one or more links coupling the upstream link partner122 and the downstream link partner 126. In this regard, the aggregatecommunication rate may be distributed evenly or unevenly among the oneor more links coupling the upstream link partner 122 and the downstreamlink partner 126 via the asymmetrical multi-rate Ethernet PHY. Thedistributed communication rate received from the upstream link partner122 or the down stream link partner 126 may be aggregated via theasymmetric multi-rate PHY. The asymmetric multi-rate Ethernet PHY mayhandle compressed and/or uncompressed video signals as well as encryptedo unencrypted video signals. Moreover, the communication signals may bemodified and/or processed by at least one of an echo cancellationoperation, a near end cross talk (NEXT) cancellation operation, a farend cross talk (FEXT) cancellation operation and/or forward errorchecking (FEC) and equalization.

Another embodiment of the invention may provide a machine-readablestorage, having stored thereon, a computer program having at least onecode section executable by a machine, thereby causing the machine toperform the steps as described herein for enabling communicating datavia asymmetric physical layer operation for Ethernet A/V Bridging andEthernet A/V Bridging extensions.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system or in a distributed fashion where different elements arespread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A system for communicating data, the systemcomprising: a first network device communicatively coupled to one ormore other network devices via one or more Ethernet links, said firstnetwork device comprising: an Ethernet medium access controller (MAC)layer configured to enable transmitting of signals that comprise AudioVideo Bridging (AVB) streams at a first data rate to said one or moreother network devices and receiving signals that comprise AVB streams ata second data rate from said one or more other network devices,utilizing AVB services with quality of service descriptors; and anasymmetric multi-rate Ethernet physical layer (PHY) transceiverconfigured to perform said transmitting of said signals and saidreceiving of said signals; wherein: said first data rate is distributedunevenly over each of four twisted-pair wires of a corresponding one ofsaid one or more Ethernet links; and said second data rate isdistributed unevenly over each of four twisted-pair wires of acorresponding one of said one or more Ethernet links.
 2. The system ofclaim 1, wherein said first data rate is not equal to said second datarate.
 3. The system of claim 1, wherein: said signals transmitted atsaid first data rate comprise one or more of audio signals, videosignals and auxiliary data signals; and said signals received at saidsecond data rate comprise one or more of control signals, configurationsignals and one or more encryption keys.
 4. The system of claim 1,wherein: said signals received at said second data rate comprise one ormore of audio signals, video signals and auxiliary data signals; andsaid signals transmitted at said first data rate comprise one or more ofcontrol signals, configuration signals and one or more encryption keys.5. The system of claim 1, wherein said asymmetric Ethernet multi-ratePHY is configured to perform signal-processing operations comprising oneor more of echo cancellation, cross talk cancellation, and equalization.6. The system of claim 1, wherein said Ethernet MAC layer is configuredto reduce one or both of said first data rate and said second data rateby reducing a symbol rate provided to said asymmetric Ethernetmulti-rate PHY.
 7. The system of claim 1, wherein said asymmetricEthernet multi-rate PHY is configured to utilize multi-level signalingfor said transmitting of said signals and said receiving of saidsignals.
 8. A method for communicating data, the method comprising: in afirst network device communicatively coupled to one or more othernetwork devices via one or more Ethernet links: transmitting signalscomprising Audio Video Bridging (AVB) streams at a first data rate tosaid one or more other network devices and receiving signals comprisingAVB streams at a second data rate from said one or more other networkdevices, utilizing AVB services with quality of service descriptors,wherein: said first network device comprises an Ethernet medium accesscontroller (MAC) layer configured to enable said transmitting of saidsignals and said receiving of said signals; said first network devicecomprises an asymmetric multi-rate Ethernet physical layer (PHY)transceiver configured to perform said transmitting of said signals andsaid receiving of said signals; said first data rate is distributedunevenly over each of four twisted-pair wires of a corresponding one ofsaid one or more Ethernet links; and said second data rate isdistributed unevenly over each of four twisted-pair wires of acorresponding one of said one or more Ethernet links.
 9. The method ofclaim 8, wherein said first data rate is not equal to said second datarate.
 10. The method of claim 8, wherein: said signals transmitted atsaid first data rate comprise one or more of audio signals, videosignals and auxiliary data signals; and said signals received at saidsecond data rate comprise one or more of control signals, configurationsignals and one or more encryption keys.
 11. The method of claim 8,wherein: said signals received at said second data rate comprise one ormore of audio signals, video signals and auxiliary data signals; andsaid signals transmitted at said first data rate comprise one or more ofcontrol signals, configuration signals and one or more encryption keys.12. The method of claim 8, further comprising performingsignal-processing operations comprising one or more of echocancellation, cross talk cancellation, and equalization on said signalsreceived at said second data rate.
 13. The method of claim 8, furthercomprising reducing one or both of said first data rate and said seconddata rate by reducing a symbol rate provided to said asymmetric Ethernetmulti-rate PHY.
 14. The method of claim 8, further comprising utilizingmulti-level signaling for said transmitting of said signals and saidreceiving of said signals.